The present invention relates generally to an improved valve or valve actuator and, more specifically, to a locking mechanism for a valve to prevent inadvertent operation thereof.
Valves are known to be used for controlling many different types of fluids, such as gases and liquids. In some cases, such fluids are highly corrosive, acidic, dangerous, and/or require extreme caution. For controlling these types of fluids, it may be desirable, and is sometimes required by safety regulations, such as OSHA regulations or other regulations, to provide means for preventing accidental operation of the valves. Preferably a padlock or a special type of padlock with a dual key locking mechanism may be utilized. Rotary valves may be especially inconvenient to lock and may require extensive modification to provide suitable locking arrangements. There may be problems with prior art locking arrangements whereby a valve can inadvertently be locked into the wrong position and where the valve may appear locked but is not actually locked.
The prior art discussed above does not provide a rotary valve locking mechanism that may be readily incorporated into a valve without modifications to the valve or a suitable valve actuator with a locking mechanism. Locking mechanisms may be difficult to incorporate into a valve without the use of additional seals and/or other elements that may deleteriously affect operation of the valve. It is also desirable that the valve assembly including any valve actuators be as compact as possible. Consequently, there remains a need to provide a highly reliable and compact valve locking apparatus and method. Those of skill in the art will appreciate the present invention which addresses the above and other problems and long felt needs.
Accordingly, it is an objective of the present invention to provide an improved valve locking mechanism.
Another object of the present invention is to provide an improved lock that may be designed to lock the valve in only one position, depending on construction, which may be either the open position or the closed position.
Yet another object of the present invention is to provide an improved valve locking mechanism that requires no modifications to the valve with which the valve lock is utilized.
Therefore, a valve locking mechanism is provided which is operable for locking a rotary valve actuator into a selected position wherein the rotary valve actuator comprises a moveable actuator element moveable between a first position and a second position. The valve locking mechanism may comprise one or more elements such as, for instance, a housing for the moveable element and a valve lock element moveable within the housing between a valve operate position and a valve locked position. Preferably, the valve lock element may be in contact with the moveable actuator element of the rotary actuator in the valve locked position to thereby prevent movement of the moveable actuator element between the first position and the second position. Moreover, the valve lock element preferably has a clearance relationship with respect to the moveable actuator element of the rotary actuator in the valve operate position such that the valve lock element then permits movement of the moveable actuator element between the first position and the second position.
Other elements may include a lock hole through the path suitable for an insertable locking device. In a preferred embodiment, the lock hole may be positioned along the path such that when the insertable locking device is inserted within the lock hole then the valve lock element is prevented from moving from the valve locked position to the valve operate position. The valve lock element may block the lock hole for the insertable locking device when the valve lock element is in the valve operate position.
The valve locking mechanism may further comprise a valve lock retainer element mounted at one end of the path to restrict movement of the valve lock element and to thereby prevent removal of the valve lock element from the housing through the one end of the path.
In one embodiment, the housing comprises an actuator housing for the rotary actuator defining a pressure containment region therein sealed for containing pressure. The valve lock element may be disposed within the pressure containment region or the valve lock element may be disposed outside of the pressure containment region. In another embodiment, the housing comprises an adaptor plate.
Thus the present invention may comprise a locking mechanism operable for locking and unlocking a rotary valve actuator wherein the rotary valve actuator comprises a rotary shaft rotatable between a first rotary position and a second rotary position. A first rotary valve actuator member may be connected for movement with the rotary shaft wherein the first rotary valve actuator member may have a first stop surface. The first rotary valve actuator member may comprise a piston operatively connected to the rotary shaft. Alternatively, the first rotary valve actuator member may be mounted to the rotary shaft for rotation with the rotary shaft. The valve lock element may then lockingly engage the first rotary valve actuator member in the valve locked position to prevent rotation of the rotary shaft between the first rotary position and the second rotary position. A second stop surface may be affixed with respect to the rotary shaft whereby the first stop surface and the second stop surface are engageable with each other to limit rotational movement of the rotary shaft. In a preferred embodiment, the valve lock element engages the first stop surface in the valve lock position. Other elements may include an adaptor plate for the rotary valve actuator wherein the valve lock element may be mounted within the adaptor plate.
A method is provided for assembling a valve locking assembly operable for locking a rotary valve actuator into a selected position wherein the rotary valve actuator comprises a moveable actuator element which is moveable between a first position and a second position. The method may comprise one or more steps such as, for instance, mounting a locking element within a housing for movement along a path defined within the housing between a valve locked position and a valve operate position, providing that the actuator moveable element is prevented from movement between the first position and the second position when the locking element is in the valve locked position, and mounting a retainer along the path to limit movement of the locking element.
Other method steps may include providing that the locking element is engageable with the retainer when the locking element is in the valve operate position, and/or providing a hole transverse to the path within the housing for insertion of an insertable lock into the hole to prevent movement of the locking element when the locking element is in the valve locked position, and/or providing that the locking element blocks the hole transverse to the path to prevent the insertable lock from being inserted into the hole when the locking element is in the valve operate position.
Other steps may also include utilizing the housing as a valve adaptor plate for mounting of the rotary actuator and/or utilizing the housing as an actuator housing and/or sealing the actuator housing to provide a pressure-sealed zone within the actuator housing for containing pressure. Additional steps may include mounting the locking element within the pressure sealed zone or mounting the locking element outside of the pressure-sealed zone.
In other words, yet another embodiment of a locking mechanism is provided that is operable for locking a valve and a valve actuator into a selected position. The locking mechanism may comprise one or more elements such as, for instance, an end stop for the valve actuator comprising a moveable member with a first moveable stop surface and a second affixed stop surface, and a valve lock element, the valve lock element being moveable between a valve operate position and a valve locked position, the valve lock element engaging the first moveable stop surface in the valve locked position.
In yet another embodiment, the invention may comprise elements such as, for instance, a valve lock element a valve lock element, the valve lock element being moveable between a valve operate position and a valve locked position, the valve lock element engaging a moveable actuator element in the valve locked position, a housing for the valve lock element, the housing defining a lock hole for a locking device, and a valve lock retainer element mounted to prevent removal of the valve lock element.
In operation, a method is provided for locking a valve into a selected position utilizing an insertable lock. The method comprises one or more steps such as, for instance, mounting a locking element for movement with respect to an actuator housing between a valve locked position and a valve operate position, and mounting a retainer with respect to the locking element such that the locking element is prevented from being removed when the insertable lock is removed.